Hydraulic jack



W. S. PINE HYDRAULIC JACK Dec. 29, i953 2 Sheets-Sheet 1 Filed NOV. 14, 1950 pal. ma a llll INVENTOR. MLL/AM \5. P/NE Dec. 29, 1953 w. s. PINE 2,664,073

HYDRAULIC JACK Filed Nov. 14, 1950 2 Sheets-Sheet 2 Jtazi 4s 4 4 IN V EN TOR. Mu. MM 5. I' /N5 Patented Dec. 29, 1953 UNITED :S'a'I'ATE-S 'PATEN T OFFICE 1. HYDRAULIC JACK 1." Williamj SJPine} LospAng'eles, Calif. *ApplicationNovember 14, 1950, Serial'No."195,'598

7 .-4i Claims.

...This invention relates generally tonlifting denvicespandparticularly to a hydraulic jack. .for ..,moving an object.- Specifically, the invention pering. at base anda vertica1ly,-;movable ram.

fine-object of theinventionisztozprovide a. hy

-- .draulic jack which includes a baseprovided with Ta vertical post,:at-.the upper .end of-which is. a .Jpistomhead, a cylindrical ram slidable. vertically on., the, pcstflandghavingi an .upper closedend, ..,means .,for .introducing pressure ,operating... fluid between the piston and the closed .endofthe ram to force the latter. upwardly, and, locking means for releasably retainingfthe ram in selected vertical positions.

.IAIlOthBl object is to. provide a hydraulic .jack Q in which the lockinsmeansg consists of interengaging means .on the ram and the postforposi- I tivelyholdingthe ram in difierent positionsof axial adjustment. .A'further object is. toprovide.a,..jack, of the I character referredto, in whichthe locking means comprises a. plurality of longitudinallyespaced ratchet teeth on its. periphery andia weightgactu ..ated.,paw1. pivoted on. the ram, and engageable ..succe.ssively.-with ,the ratchet teetheas the-ram is raised, sov as. to preventaccidental release and loweringoitheramin the event ofiailure of the hydraulic. system. 7 HA further object istoyprovide ahydraulic.-jack .ofthe type indicated in: which saidxratchet teeth .zare formed atone side .of rthe;post, theihottom of the spaces between the teeth beingstraightand extending transversely .of the post, -.and in which the pawlis pivoted on an, axis extending parallel to said bottoms of the teeth, the-pawl having a straight end adapted oo-engage said: bottomsv of ,-;the .teeth so..as to, keyqithegpost and ramgagainst -relative: rotation. A 2 still .further object of they, inventicnxis 1 to :provide a: hydraulic "jack :"f; the. type: specified -:::=whi.ch .iis; highly:- eificient in operation, adapted 1' a" for: heavy. duty; and one which rcan-i-be: employed w-with .positivesafety.

Further objectswvill appearirom the followingdescription-and from the drawings, which are" isentimprovements. are shown as embodied in. a

. hydraulic jack of the lifter type disclosed inmy copending application for patent on Hydraulic Jack, Serial No. 30,999, filed March 11, 1949, and

1 now Patent No. 2,654,568, issued October 6, 1953. The jack includes a flat base 5 adapted .to rest upon a. how or other. supporting surface. ..An

upright. or post 6 is welded or otherwise suitably-secured to andprojects upwardly from' the base and has its upper end reduced in diameter to receive apiston head I, the head having peripheral grooves in which are disposed sealing rings 8 and 9. A cylindrical ram H! has a. tu-

bular portion Il-slidable axiallyon the post 6,

the end wall .12 oftheram mso as to forcelthe ram upwardlywto. perform a lifting operation.

The hydraulic fluid. is introduced through the vubore 14 by means to be next described.

-Disposed alongsidethe post 6 is a vertical receptacle 19 having walls defining a reservoir 20 for containing .acsupply of hydraulic fluid 2i, the receptacle having a filler plug 22. Actu- 2 atingpumps23-and 24 are disposed at thesides of the postlfi each pump including a cylinder theupper ends of. the pistons 26 are, 'pivotally 25 and a-piston 26 slidable vertically therein. To

,connected operating leversj 21. which area'lso npivotallyconnected to the upper ends of links -28,pivotedto*the base .atf29. The levers .21 have forwardly. extending. ends to which tubular handleanot shown, may be detachably connected.

..Upon the upward stroke of. each piston 26','.fluid -isxdrawn from the bottomof the. reservoir 20 through apassage 30 leading from the reservoir into the .lowerendof the cylinder 25. l A ball check valve -31 vis provided in each passage 3U forv preventing. now of. the fluid from i the cylineder. .25 back to the reservoir 2E1.

,The lower end of. each cylinder 25 communi- "cates with. the bore 14 ofthe .post 6 by way of a ..transverse passage 33 and a port 34, aball check "valve 35=being disposed in the bottom of the cylin- -der '25 to prevent return of the fluid fromthe rbore ll into the cylinder 25 when the piston 26 is raised.

9 Aireturn. passage .40 connects with :the trans- ":verse passageJ33 andhas an'enlarged portion or Mchamber 4!, the annularcshoulder between the passage '40 and the chamber 4 l" providing a seat 42. -:1A-vertical#tube 43 has itslowerlendinz fluid communication with the chamber 4|, the tube extendin upwardly within the reservoir 20 with its upper end disposed adjacent the upper end of the reservoir. A ball 45 is disposed within the chamber 4| and is adapted to be forced against the seat 42 to close the return passage 40 so as to prevent return of fluid from the bore [4 to the reservoir 20 and thus tra the operating fluid within the bore [4 and the ram It) to retain the latter in raised position. A pressure relief passage 41, extending from the transverse passage 33, communicates with the lower end of the reservoir 20 through a port 48. An adjustable springactuated valve disc 49 in the passage 41 is adapted to open when the fluid pressure in the system exceeds a predetermined value so as to reduce the pressure and thus prevent damage to the various components of the jack.

It will be apparent that when the ball 45 is seated by means of a locking stem 50 having a screw-threaded forward end and one or both pumps 23 and 24 operated, alternately or simultaneously, fluid is drawn from the reservoir and forced through the passage 33 into the bore l4 of the post and against the end wall [2 of the ram Ill. The ram is thus forced upwardly to lift the object under which the jack is disposed. After the object has been raised to the desired height the pumping action i discontinued, and since the fluid is trapped in the post 6 by the ball valves 35 and the ram I8 is retained in its raised position. When it is desired to lower the object the locking stem is merely unscrewed, so as to allow the ball 45 to move away from its seat 42. mitted to flow from the bore [4, through the passages 33, 40 and the tube 43, into the reservoir 20.

The hydraulic jack described above is more or less conventional in construction. It is well known that such conventional hydraulic jacks are occasionally subject to failure due to escape of the operating fluid from the actuating cylinder or ram, or past the ball check valves. When this condition prevails the ram may descend, either slowly or rapidly, depending upon the rate of leakage of the fluid. Another disadvantage of hydraulic jacks of previous types is that the ram, which directly supports the object being lifted, is free to rotate and this frequently allows the supported object to shift with respect to the jack and causes upsetting of the jack. It has been stated that the important objects of the present invention are to provide means for positively locking the ram in selected positions of axial adjustment and for keying the ram against rotation with respect to the base of the jack so as to guard against both accidental lowering and rotation of the ram. This locking and keying means, which is embodied in a single instrumentality, is constructed and arranged as next described.

The stationary post 6 of the hydraulic jack is provided at its forward side with a fiat surface 60 which is milled to provide a plurality of vertically-spaced ratchet teeth 5| having V-shaped spaces 62 therebetween. Adapted to engage in the tooth spaces 62 is the pointed end of a pawl which is pivoted on a pin 66 carried by a bifurcated boss 6'! at the forward side of the lower end of the ram ID, the pin extending parallel to the fiat surface of the post 6. The pawl is of such a size and is so positioned that a portion thereof will engage the flat surface 63 to prevent rotation of the cylinder with respect to the post even though the tooth engaging edge of the pawl 65 is out of engagement with the ratchet teeth 6|.

By this action the operatin fluid is per- 4 Projecting forwardly from the pawl 65 is a handle 69 which carries a weighted knob 10 at its free end.

The weight 10 normally pivots the pawl 55 in clockwise direction, as viewed in Fig. 4, so that as the ram I0 is forced upwardly the pointed end of the pawl rides successively over the ratchet teeth. When the ram has been raised to the selected position, the pawl 65, due to its engagement with one of the ratchet teeth 6|, locks the ram in its elevated position to prevent accidental lowering thereof. The pawl thus functions as a safety device.

When it is desired to lower the ram, the pawl is pivoted in counterclockwise direction by means of the handle 69, as indicated in broken lines in Figs. 2 and 4. To permit such pivotal movement of the pawl, the ram It] may be raised slightly by means of a pump 23 or 24.

Referring to Fig. 3, it will be seen that due to the engagement of the straight end of the pawl 65 with the fiat surface 60, or the straight bottom of a tooth space 62, the ram is keyed against rotation on the post 6 at all times.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by modified means.

I claim as my invention:

1. A hydraulic jack, comprising: a post having a piston at one end thereof and having longitudinally spaced ratchet teeth in its periphery, the bottom of the spaces between the teeth being straight and extending transversely of the post; the tops of the teeth being straight and providing a broken substantially flat surface; a cylindrical ram slidable axially on the post and having a closed end; means for introducing pressure operating fluid between said piston and said closed end of the ram to effect relative axial sliding movement of said post and said ram so as to extend the length of the jack; a pawl carried by said ram and pivoted on an axis parallel to said straight bottom of said tooth spaces, said pawl having a straight end engageable in successive tooth spaces during extension of the jack so as to lock said ram in selected positions of axial extension, engagement of said straight end of said pawl in said straight bottom of said tooth spaces serving to key said ram and said post against relative rotation; said pawl having a portion extending within the cylindrical outline of said post at all times, serving to prevent rotation of said ram regardless of the position of the straight end of the pawl and a weighted operating handle carried by said pawl and projecting radially and laterally from the pivotal axis thereof, said handle maintaining said pawl in engagement with said ratchet teeth and adapted, when raised to release said pawl from said teeth.

2. A hydraulic jack comprising a generally cylindrical post having a non-circular surface portion, ratchet teeth on said portion, a piston on one end of said post, a cylinder closed at one end and slideably received on said post and said piston, a member pivotally mounted on the open end of said cylinder having a body portion projecting inside the cylinder for contacting said non-circular portion of said post to prevent ro tation, a pawl on the said body portion adapted to engage said non-circular surface and the tip of said pawl releaseably engaging said ratchet teeth for preventing movement of the cylinder in one direction, and means to force fluid between the closed end of said cylinder and said piston for causing movement of the piston in the opposite direction.

3. A hydraulic jack comprising a generally cylindrical post having a flat surface portion within the cylindrical outline, ratchet teeth in said surface portion, a piston on end of said post, a cylinder closed at one end and slidably received on said post and said piston, a member pivotally mounted on the open end of said cylinder having a body portion projecting inside the cylinder for contacting said flat surface portion of said post to prevent rotation, a pawl on said body portion adapted to engage said flat surface and the tip of said pawl releasably engaging said ratchet teeth for preventing movement of the cylinder in one direction, and means to force fluid between the closed end of said cylinder and said piston for causing movement of the piston in the opposite direction.

4. A hydraulic jack comprising a generally cylindrical post having a non-circular surface portion, one end of said post providing a piston, a cylinder closed at one end and slideably received on said post and said piston, a memher movably mounted on the open end of said cylinder having a portion extending within the cylindrical outline of the post at all times adapted to engage said non-circular surface to prevent rotation of said cylinder at all times and an edge releasably engaging said surface for pre venting movement of the cylinder in an axial direction, and means to force fluid between the closed end of the cylinder and the piston for causing movement of the piston in the opposite direction.

WILLIAM S. PINE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,435,128 Newman Nov. 7, 1922 1,512,837 Evenden Oct. 21, 1924 1,526,563 Powers et a1 Feb. 17, 1925 1,590,848 Nilson June 29, 1926 FOREIGN PATENTS Number Country Date 15,859 Great Britain Sept. 3, 1892 27,668 Great Britain Dec. 5, 1906 7,553 Great Britain Mar. 28, 1907 351,884 Germany July 26, 1922 

